Giant Cell Arteritis

Giant Cell Arteritis is a systemic vasculitis affecting large and medium-sized arteries, with primary involvement of the external carotid artery system and its branches, particularly the temporal artery. The disease results from T cell-mediated granulomatous inflammation with characteristic giant cells and macrophage infiltration of the vessel wall. Pathologic findings typically show granulomatous inflammation with giant cells centered at the internal elastic lamina. The inflammatory process causes vessel wall necrosis and intimal proliferation, leading to stenosis and ischemia in affected territories. Headache, often severe and localized to the temporal arteries, is the most common presenting symptom in 70%. Visual symptoms develop in 15-20% of untreated patients, including amaurosis fugax (transient vision loss) and permanent blindness from arteritic anterior ischemic optic neuropathy, a medical emergency requiring immediate high-dose corticosteroids. Jaw claudication (pain with mastication) is highly specific. Constitutional symptoms including fever, fatigue, and weight loss occur. Large vessel involvement (aorta, subclavian, axillary arteries) occurs in 10-15% and can cause significant ischemic complications. Polymyalgia rheumatica commonly co-occurs.